Within the past decade many efforts have been made to reduce costs and environmental pollution during the treatment of substrates. One of the effective means developed has been the use of foam or froth to apply the treating composition to the substrate. Particularly effective has been the use of the foams described and claimed in U.S. Pat. No. 4,099,913 issued on July 11, 1978 to Walter et al and the apparatus described and claimed in U.S. Pat. No. 4,023,526 issued on May 17, 1977 to Ashmus et al, both assigned to Union Carbide Corporation. The technology disclosed in these two patents has found wide international commercial acceptance in the textile and paper industries, particularly in the treatment of close-weave fabrics such as sheeting, denim, corduroy, chambray, twill, non-woven and similar textile materials, and paper products. While this technology can also be used to apply foams to open-weave fabrics such as casement, leno or lace, there has been some difficulty in achieving uniform application to both sides of the open-weave products; the equipment and method disclosed in this application overcome many of the difficulties heretofore experienced with such fabrics.